Ethynylation catalyst catalyst preparation and process

ABSTRACT

PARTICULATE CATALYST, CONSISTING ESSENTIALLY OF CUPROUS ACETYLIDE COMPLEXES CONTAINING AT LEAST 1.75 CARBON ATOMS PER COPPER ATOM, AND HAVING A TOTAL SURFACE AREA OF AT LEAST 5.0 SQUARE METERS PER GRAM, ARE PREPARED AT 50120*C. BY THE SIMULTANEOUS ACTION OF FORMALDEHYDE AND ACETYLENE AT A PARTIAL PRESSURE OF LESS THAN 2.0 ATMOSPHERES ON CUPRIC COMPOUNDS SLURRIED IN SUBSTANTIALLY NEUTRAL AQUEOUS MEDIA AND USED TO CATALYZE ETHYNYLATION IN A CONTINOUS STIRRED REACTION AT 60-120*C. AND ACETYLENE PARTIAL PRESSURES BELOW 2.0 ATMOSPHERES.

United States Patent Int. Cl. C07c 33/04 11.8. Cl. 252-431 23 ClaimsABSTRACT OF THE DISCLOSURE Particulate catalysts, consisting essentiallyof cuprous acetylide complexes containing at least 1.75 carbon atoms percopper atom, and having a total surface area of at least 5.0 squaremeters per gram, are prepared at 50- 120 C. by the simultaneous actionof formaldehyde and acetylene at a partial pressure of less than 2.0atmospheres on cupric compounds slurried in substantially neutralaqueous media and used to catalyze ethynylation in a continuous stirredreaction at 60-120 C. and acetylene partial pressures below 2.0atmospheres.

CROSS-REFERENCE TO RELATED APPLICATION This is a division of applicationSer. No. 677,020, filed Oct. 23, 1967, now Patent No. 3,560,576.

BACKGROUND Copper acetylide complexes have hitherto been prepared invarious ways and used to catalyze ethynylations, typically the reactionof formaldehyde with acetylene to produce butynediol, cf. Hanford et al.Ind. and Eng. Chem. v. 40, No. 7, pp. 1171-1177 (1948); Reppe AcetyleneChemistry PB Report 188528, Meyer translation, pp. 77-92 (1949); Reppe,Chemie-Ingenieur-Technik, v. 22, No. 23/24 pp. 527539 (1950); Reppe etal. Annalen 596 pp. 6-10 (1955); US. Patents 2,232,867; 2,300,969;2,487,007; 2,712,560; 2,768,215; 2,840,618; 2,871,273; 2,939,844 and3,154,589 and British specification 698,019.

Because these prior art complexes per se have been readily explosive,difficult to filter, and active in catalyzing cuprene formation, theyhave typically been prepared and used together with siliceous orcarbonaceous supports to facilitate handling and together with a bismuthcompound to minimize cuprene formation. Commonly, the siliceous supportshave been impregnated with a solution of bismuth and copper nitrates,dried, calcined to produce the metal oxides, and the copper oxideconverted to an acetylide in situ in the ethynylation reactor.

In order to achieve lowest ethynylation operating costs, it hasgenerally been preferred to use these supported catalysts in pilled formin a fixed-bed plug flow process, feeding dilute aqueous formaldehydeand employing multipoint injection of acetylene at relatively highpressure, so as to use up excess formaldehyde and minimize the extent ofdistillation required to produce product of the requisite purity. Anundesirable feature of this approach, however, has been the high initialcost of reactors designed to withstand not only the normal operatingacetylene pressures of 2 to 6 atmospheres, but also the higher pressuresof up to times greater than normal which occur coincidentally with theoccasional development of hot spots in such fixed bed systems.

It has also been proposed to employ such supported catalysts as slurriesin continuous stirred reactions. Hitherto in such systems, however, notonly has it been found necessary to remove and purify the catalyst atfrequent intervals to avoid fouling, but also, even with continuouscomplete catalysts removal, purification and recycle, it has beennecessary to operate at relatively low formaldehyde conversions andrelatively high acetylene partial pressures to achieve even marginallyacceptable space/ yields. Such processes have, therefore, involvedhigher operating costs than fixed-bed plug flow processes, because ofhigher product separation expense, and offered little in the way ofinitial equipment savings, because of the relatively high operatingpressures required.

SUMMARY OF THE INVENTION In accordance with the present invention, thereare provided particulate ethynylation catalysts, consisting essentiallyof cuprous acetylide complex containing at least 1.75 carbon atoms percopper atom, and having a total surface area of at least 5.0 squaremeters per gram.

There are further provided processes which comprise subjecting aparticulate cupric compound, as a slurry in a substantially neutralaqueous medium at 50 to C., to the simultaneous action of formaldehydeand acetylene at a partial pressure of less than 2.0 atmospheres untilthe above-described catalysts are obtained.

There are further provided processes which comprise contacting carbonylcompound and acetylenica'lly unsaturated hydrocarbon at a partialpressure of less than 2.0 atmospheres with the above-described catalystas a slurry in an aqueous medium in a continuous stirred reaction at60120 C.

DETAILED DESCRIPTION The catalysts of the invention essentially contain,and may consist entirely of, the particular class of copper acetylidecomplexes hereinafter described. While the catalysts may also containother materials, e.g., supports such as carbon or silica, cupreneinhibitors such as hismuth oxide, acid acceptors such as calciumcarbonate, other copper acetylide complexes, unconverted catalystprecursors of residues therefrom, and the like, such extraneous materialdo not noticeably enhance and may detract from the filterability andactivity of the catalysts of the invention, and accordingly are regardedas nonessential. In one preferred form of the invention, the catalystsconsist of this particular class of copper acetylide complexes, per se.

The cuprous acetylide complexes of the invention are products resultingfrom the combination and/or association of the copper acetylide Withintermediates involved in the catalyst preparation and/or ethynylationreactions. Repeated water washing produces products in which thecarbon/copper ratio does not change on further water washing, andanalyses of such products when prepared from intermediates containingradioactive carbon show radioactivity deriving from both carbonylcompound and acetylenic compound. Mild degradation of the complexes withaqueous sodium cyanide produces acetylenic hydrocarbon and oxygenatedacetylenic hydrocarbon. Ordinarily, continued drying of the complexesresults in a change of composition corresponding to a loss of water.

As determined by combustion analysis of these catalysts, afterfiltering, water washing, air drying, and final drying over anhydrouscalcium sulfate for three days, and correcting for the weight of anycomponents present other than copper acetylide complexes, the particularcomplexes with which the present invention is concerned contain at least1.75 carbon atoms per copper atom. The atomic ratio of carbon to copper,so determined, is ordinarily 2.0 to 12.5 and 2.5 to 5.0 in the preferredcomplexes. Where such analysis also affords unequivocal results forhydrogen, the complexes of the invention generally also contain at least0.2 hydrogen atoms per carbon atom. The C/H atomic ratio so found isordinarily greater than 0.5 and 1.0 to 2.0 in the preferred complexes.Similarly, where oxygen is taken as the difference between 100 percentand the summation of the percentages of copper, carbon and hydrogen inthe complexes thus determined, after making due allowance for any oxygenassociated with other elements present, such as calcium or silicon, thecomplexes generally contain at least 0.1 oxygen atom per carbon atom,ordinarily less than 1 oxygen atom per carbon, and usually 0.15 to 0.5oxygen atoms per carbon atom in the preferred complexes. Ordinarily, thecomplexes contain 20.0 to 66.0 and preferably 40.0 to 62.0 percentcopper, based on the total weight of copper, carbon, hydrogen and oxygenfound to be contained in the complex by the above procedures.

In the complexes of the invention, per se, the copper, as determined bydegrading the complexes, with e.g. concentrated HCl and analyzing theresulting solution by standard quantitative analysis techniques, issubstantially entirely in cuprous form, there being found only traceamounts of cupric copper, corresponding to the amounts obtained onexposing cuprous solutions to air for the short period needed for theanalysis operations. In preparing the catalysts of the invention fromcupric precursors, the fraction of total copper in cuprous form is takenas a measure of the amount of complexed copper. Ordinarily, theparticulate catalysts of the invention contain 20.0 and 66.0 percent,and preferably 40.0 to 62.0 percent cuprous copper, based on the totalweight of the particulate catalyst, after filtering, Washing and dryingas above described.

Comparison of the empirical values determined for copper content andatomic ratio of the several elemental components of the complexes withthe calculated values for various formulas such as those set forth inTable I below shows that these complexes of the invention respond moreclosely to the formula where the subscript letters are integers, w, xand y being at least 1 than to the formula (CU C ),(C H ),,(H O) wherethe subscript letters are integers. In the preferred complexes x=l to 2yand x+2y=0.5 to 1.5w. Ordinarily each integer is less than 100.

The particulate catalysts of the invention have a total surface area ofat least 5.0, ordinarily 5.0 to 75.0 and preferably at least 15.0 squaremeters per gram, as determined by nitrogen absorption measurement on theparticles after separating and drying as for combustion analysis.

In general, it has been found, active acetylide complexes in catalystsprepared from cuprous compounds, or from cupric compounds in such a waythat a substantial proportion of the cupric compound is reduced tocuprous before formation of the acetylide, tend to have carbon to copperatomic ratios of less than 1.75 as initially prepared in which conditionthey are in the form 4 of small, sticky, relatively explosive particles,commonly containing appreciable amounts of metallic copper, asdetermined by the presence of peak pairs associated with metallic copperon X-ray diffraction analysis, and commonly cointaining more than 25weight percent of particles having a cross-sectional dimension of lessthan 5.0 microns as determined by Coulter Counter analysis. Suchcomplexes are ill adapted for use in continuous stirred reactions,because of their instability, because of their tendency to blind thefilter elements through which the effiuent from a heterogeneouslycatalyzed continuous stirred reaction is continuously removed, andbecause of their tendency to form cuprene in contact with acetylene.Furthermore, while the atomic ratio of carbon to copper in such catalystcomplexes will appear to rise above 1.75 with continued use forethynylation, possibly as the result of cuprene formation, at the sametime the total surface area of the catalyst as determined by nitrogenabsorptlon tends to decrease to less than 5.0 square meters per gram,with such attendant loss in catalytic activity as to provideunacceptably low space/ time yields of ethynylation product at acetylenepartial pressures of less than about 5 atmospheres. Similarly, it hasbeen found, copper acetyllde catalysts prepared from cupric compoundsunder acetylene partial pressures of greater than 2.0 atmospheres, or inthe absence of formaldehyde, or in the presence of radically unbalancedamounts of acetylene of formaldehyde, or from cupric compounds which arehighly soluble or dispersed in media where the copper tends to dissolve,tend to have low total surface areas which may well be below 5.0 squaremeters per gram. Thus, the catalysts of the present invention, inconsisting essentially of copper acetylide complexes in which the atomicratio of carbon to copper is at least 1.75, and in having at the sametime a total surface area of greater than 5.0 square meters per gram,are distinguished from the ethynylation catalysts of the prior art.coincidentally therewith, they possess a hard granular character, astability and an ethynylation activity which renders them uniquelyattractive for use in continuous stirred ethynylation at low pressure.

Ordinarily, the catalysts of the invention are further characterized asbeing substantially free of metallic copper, as determined by theabsence of peak pairs associated with metallic copper on X-raydiffraction analysis. Small amounts of metallic copper may occasionallyby present, possibly resulting either from the use of precursorcontaining appreciable amounts of cuprous compound or appreciableamounts of soluble cupric compound. Presence of metallic copper tends tofoster cuprene formation, which, however, can be minimized by includingbismuth compounds in the catallyst.

Ordinarily, the catalysts of the invention are further characterized inthat at least and usually at least or more weight percent of thecatalyst is in the form of particles having a cross-sectional dimensionof at least 5, ordinarily 5 to 40 and preferably 8 to 30 microns asdetermined by Coulter analysis. The size of the average particle ispreferably 10 to 20 microns for optimum combination of filterability andactivity. In particularly preferred catalysts substantially all of theparticles are larger than 3 microns in at least one cross-sectionaldimension.

The particulate catalysts of the invention are prepared by atopochemical reaction occurring at the surface of particles of cupriccompound slurried in an aqueous medium at the reaction temperature. Thetopochemical reaction continues to convert successive layers of thecupric compound as the reaction proceeds, leading ultimately toparticulate complexes in which the cupric compound is completelyconverted to cuprous acetylide. For reasons already indicated, thetopochemical reaction as well as the cupric form of the precursor appearessential to obtaining the desired results. Accordingly, although anycupric precursor of limited water solubility can be used as anintermediate, and solubility in the particular aqueous medium employedcan be further minimized by controlling the pH of the aqueous medium,advantageously the cupric precursor will be substantially free ofcuprous and soluble cupric compounds. Illustrative of insoluble cupriccompounds are cupric oxide, cupric silicate, cupric phosphate, cuprichydroxide, basic cupric carbonate, and the like. Of these, the basiccupric carbonates are particularly preferred because of the rapiditywith which active catalysts can be prepared from them, and because ofthe superlative filterability, purity, stability, and activity of theresulting catalysts.

A list of useful basic cupric carbonates appears in the Kirk-OthmerEncyclopedia of Chemical Technology, first edition, volume 4, page 469.Carbonate having the empirical formula Cu CH O usually written asmalachite, is preferred for availability. Since contamination of theinsoluble cupric precursor with minor amounts of soluble cupric salts,particularly those of oxidizing acids such as sulfuric, as usually foundin the naturally occurring mineral, has an adverse effect on thecatalyst obtained, it is particularly preferred to use a highly puresynthetic malachite derived from the reaction of cupric nitrate and asoluble carbonate, with a calculated CuO/CO mole ratio of 1.0 to 3,0,preferably 1.80 to 2.20, and ideally about 2.0, which assays less than0.2 weight percent of sulfur, calculated as sulfate ion. Some control ofthe total surface area and particle size of the ultimate catalysts canbe achieved by control of the size and distribution of particle sizes ofthe precursor particles. The particles tend to grow in cross-section asthe conversion to acetylide proceeds. Preferably, the precursorparticles will be substantially all larger than 2.0 microns incross-sectional dimension, as determined by Coulter Counter analysis,and will have a total surface area of at least 5.0 square meters pergram as determined by nitrogen absorption In preparing the particulatecomplexes of the invention, the slurried cupric precursor is subjectedto the simultaneous action of formaldehyde and acetylene at a partialpressure of not more than 2.0 atmospheres in a substantially neutralaqueous medium at 50-120 C. At temperatures substantially outside thisrange, or in strongly basic or acidic media, or at acetylene partialpressures greater than 2.0 atmospheres, or in the substantial absence ofeither formaldehyde or acetylene, catalysts of low total surface areaand low ethynylation activity tend to result. Preferably, the catalystpreparation temperature is in the range of 60 to 90 C. The pH of theaqueous medium is in the range of 3.0 to 10.0, advantageously 5.0 to8.0, and preferably -6.0 to 7.0, at the outset of the reaction. Theconcentration of formaldehyde in the aqueous medium is ordinarily in therange of 1.0 to 66.0, advantageously at least 5, and preferably to 40weight percent, at the outset of the reaction. Ordinarily, the amount ofliquid medium will be such as to provide 5 to 20 moles of formaldehydeper gram atom of cupric copper in the precursor. Ordinarily, the partialpressure of acetylene over the aqueous medium is in the range of 0.001to 2.0 atmospheres; advantageously it is in the range of 0.005 to 0.5,and preferably 0.01 to 0.3 atmosphere per weight part of formaldehydepresent in 100 parts of the aqueous liquid medium, but less than 2.0atmospheres.

In carrying out the catalyst preparation, nitrogen or othersubstantially inert gas such as methane or carbon dioxide may bepresent, as may also common components of crude acetylene, such asmethyl acetylene and ethylene. Oxygen is preferably excluded for safetyreasons. In small catalyst batches, the particulate cupric compoundprecursor may be slurried in cold neutral formaldehyde solution and theacetylene introduced as the slurry is heated. For larger batches, it ispreferable for reasons of safety to introduce the cupric precursorincrementally to hot neutral formaldehyde solution under acetylenepressure. The aqueous solution may advantageously be a stream containingpropargyl alcohol and/ or butynediol, e.g. a recycle stream.

The catalyst preparation reaction is preferably continued until thecopper is substantially completely converted to cuprous acetylide,which, with the preferred carbonate precursors, generally requires 1 to4 hours after all the precursor has been contacted under the prescribedconditions, and with other precursors substantially longer. Preferably,also, the prescribed conditions of temperature, pH andacetylene/formaldehyde concentration balance and range will bemaintained throughout the catalyst preparation period. However, minordepartures from the prescribed conditions during the course of thepreparation reaction can be tolerated, inasmuch as only a portion of theoverall reaction is occurring at any given moment.

The pH of the aqueous medium normally decreases as the reactionproceeds, at a rate and to an extent which tends to increase with theinitial acidity of the reaction medium and also with the reactiontemperature. Accordingly, the pH may be, and advantageously is,controlled to some extent by beginning at the preferred initial pH of6.0 to 7.0, and to some extent by operating in the preferred temperaturerange of 60 to 90 C. Additional control may be achieved by adding smallamounts of acid acceptor such as calcium carbonate as the reactionproceeds. Further control may be achieved by carrying out the catalystpreparation as a continuous stirred reaction, fresh neutral formaldehydesolution being continuously introduced into an agitated reaction zone,and acidic effluent being filtered away from the copper containingparticles as the reaction proceeds, all the while maintaining acetylenepressure.

The ethynylation process of the invention comprises contactingformaldehyde and acetylene at a partial pressure of not more than 2.0atmospheres with an aqueous slurry of the catalyst of the invention in acontinuous stirred reaction at 60-120 C. In the continuous stirredreaction, formaldehyde and acetylene are continuously fed into areaction zone where they are introduced into, and preferably below thesurface of, the aqueous catalyst slurry, and thoroughly mixed into sameby mechanical stirring, gas agitation, sonic Waves or other means, andeflluent is continuously withdrawn through filter elements immersed inthe agitated catalyst slurry.

The amount of catalyst used in the ethynylation process is not critical,but is preferably such as to provide 1 to 10 Weight parts of cuprouscopper per 100 weight parts of aqueous medium. The reaction temperatureis desirably 60-120 C., advantageously -115 C., and preferably *100 C.Advantageously, the pH of the reaction mixture will be in the range of3.0 to 10.0 and preferably 5 to 7, and may be maintained by ion exchangeor acid acceptor treatment of the continuous feed. It is important forcontinued maximum ethynylation activity that a proper balance betweenformaldehyde and acetylene be maintained while either is in contact withthe slurry at reaction temperature, and that when the reaction isstopped, the formaldehyde concentration, acetylene partial pressure andtemperature all be lowered at approximately the same time, e.g., bysubstituting cold water for the aqueous formaldehyde feed and inert gassuch as nitrogen for the acetylene feed at the same time.

The formaldehyde concentration in the liquid medium in contact with theslurried catalyst during the course of the ethynylation reaction will beordinarily 1 to 66, advantageously at least 5, and preferably about 10weight percent under steady state conditions. The acetylene partialpressure will ordinarily be at least 0.001 atmosphere. Advantageously,the acetylene partial pressure will be in the range of 0.005 to 0.5atmosphere per weight part of formaldehyde present in parts of saidmedium. Preferably, the acetylene partial pressure will be 0.01 to 0.3atmosphere, per weight part of formaldehyde present in 100 parts of saidmedium, but not over 2.0 atmospheres. For the purpose of the presentinvention, in the substantial absence of extraneous gas, the acetylenepartial pressure may be taken as the absolute pressure less the vaporpressure of water at the reaction temperature. As in catalystpreparation crude acetylene may be used, but for safety reasons isadvantageously substantially free of oxygen.

The concentration of formaldehyde in the feed to the continous stirredreaction will be ordinarily at least 1 percent, advantageously at leastpercent and preferably to 66 weight percent in order to achieve maximumspace/time yields of propargyl alcohol and butynediol. The rate offeeding formaldehyde will then be ordinarily such as to result in atleast and preferably to percent formaldehyde conversion across thereaction zone.

The efiluent from the reactor is then heated and/or subjected to reducedpressure to volatilize formaldehyde, propargyl alcohol and a portion ofthe water which are condensed and combined with supplementalconcentrated formaldehyde for recycle to the ethynylation reactor,purging any build-up of methanol at convenient intervals in a continuousoperation, and sending the balance of the effluent as aqueous butynedioldirectly to hydrogenation. Alternatively, effluent from the continuousstirred reaction mya be fed to a conventional plug flow ethynylation toreact any excess formaldehyde.

The invention is more specifically described and explained by means ofthe following illustrative and comparative examples in which, except asotherwise specified, all parts and percentages are on a Weight basis,and all catalysts have a total surface area of at least 5.0 squaremeters per gram.

Example 1 To a glass reactor of ca. 450 parts water capacity werecharged, at ambient temperature (a) 400 parts of aqueous 20-35 percentformaldehyde solution having a pH of 6.0 to 7.0 and an acid content,calculated as formic acid, of 10 or less part per million, and

(b) 30 parts of particulate basic cupric carbonate, (malachite), CuCo'Cu(OH) having a sulfur content, calculated as S0,, of less than 0.2percent, a copper contant and evolvable CO content corresponding to aCuO/CO mole ratio in the range of 1.80 to 2.20, a total surface area ofat least 2 square meters per gram, the particles comprising at least 75percent, as determined solids washed free of liquid reaction medium withdistilled water. A portion was dried at ambient temperature overanhydrous calcium sulfate for 3 to 5 days. Portions of the dried sampleweer analyzed (a) by combustion and standard quantitative analysisprocedures to determine the copper, carbon, and hydrogen content, thebalance then unaccounted for being taken as oxygen, (b) by X-raydiffraction to determine the presence or absence of peak pairsassociated with metallic copper, (c) by nitrogen absorption techniquesto determine total surface area; portions of the wet by Coulter Counterto determine the range of particle sizes and average particle size. Thebalance of the slurry particles were repeatedly washed with water andresulting aqueous slurry tested for catalytic activity in theethynylation of formaldehyde. The activity was tested under standardconditions in a batch reaction in a stirred glass reactor of ca. 450parts water capacity. The catalyst slurry was charged to the reactoralong with aqueous formaldehyde, producing a slurry of the catalyst in400 parts of liquid medium containing 20 to 35 percent formaldehyde atroom temperature. More acetylene than needed for reaction was bubbledinto the slurry, and the excess vented, generally at an exit rate in therange of 0.01 to 0.1 liter per minute, and the reactor contents thenrapidly heated to C. during 3 to 10 minutes. Partial pressure ofacetylene at the 90 C. temperature was 0.5 atmosphere. Small samples ofthe reaction liquor were removed at intervals and analyzed forformaldehyde. Activity was expressed in two ways. In the first,hereafter referred to as I, it was expressed either as the percentage offormaldehyde charged which reacted in two hours, or other time in hoursspecified, after commencement of heating to achieve these standardconditions. In the second, it was expressed as the rate at which thenatural logarithm of formaldehyde concentration, per hour after startingheat, was decreasing under these standard conditions at the instant when80 percent of the formaldehyde charged had reacted. Mathematically, thislatter value, hereafter referred to as J, is the slope of the tangent,at the indicated point, of the curve obtained by plotting log percentformaldehyde concentration versus hours of reaction time. In separatetests, the 1" value was found to be closely proportional to the space/time yields of butynediol obtained when using the catalyst in acontinuous stirred ethynylation reaction such as described in Examples45 to 50.

A typical set of results of such preparation, analysis and testing wasas follows:

Calculated For (CuCr) W( 2O)X( 2 r)y(HzO)n A. Percent copper incatalyst. B. Atomic ratio C/Cu in catalyst C. Atomic ratio C/H incatalyst" D Atomic ratio C/O in catalyst Copper metal by X-raydiffraction...

F. Catalyst surface area, M per gram G. Weight percent of catalystparticles ha H. Average particle size, microns ditions.

J. Activity, rate at which natural log of formaldehyde concentrationdecreasing per hour of Activity, percent formaldehyde reacted in twohours or hours specified under standard conreaetion time when 80 percentof formaldehyde charged reacted under standard conditions.

by Coulter Counter analysis, of particles having a crosssectionaldimension of at least 2 microns.

The charge was stirred, purged with acetylene, heated during about 10minutes to 65-75 C., and then maintained with stirring for 3 to 4 hoursat 6575 C. under a total pressure of 1.0 to 1.5 atmospheres absolute,corresponding to an acetylene partial pressure of 0.6 to 1.25atmospheres, the acetylene being continuously introduced below thesurface of the liquid and gas being continuously vented through a reliefvalve exiting from the top of the reactor.

On the order of l to 5 percent of the resulting slurry was removed fromthe reactor, filtered, and the retained Example 2 The general procedureof Example 1 was repeated except that the aqueous medium used incatalyst preparation also contained 3.2 percent propargyl alcohol, withthe following results, referring to the letters of Example 1.

Calculated for w/x/y/z=l2/4/4/5 (percent): A, 55.9; B, 3.0; C, 1.4; D,4.0. Found (percent): A, 55.9; B, 3.0; C, 1.4; D, 4.0; I, 92.

Example 3 The general procedure of Example 1 was repeated except thatthe aqueous medium used in catalyst preparation contained 0.75 percentpropargyl alcohol, 38.6 percent 10 In Examples 10 and 13, when w=4, thew/x/y/ z values correspond to 4.0/0.24/0.24/ 1.41 and 4.0/ 1.20/ 0.80/2.80

Examples 16-22 The general procedure of Example 1 was repeated severaltimes but at the below-indicated initial pH values of the aqueous mediumfor catalyst preparation, achieved by Acetylene partial Initial Temp.pressure pH 0.) (atm.)

adding sodium carbonate or formic acid to the rcactio sures and initialformaldehyde concentrations, for catalyst 10 medium. preparation, withresults as follows, referring to the letters of Example 1, and includingw/x/y/z values of complexes of approximately the same calculatedanalysis.

respectively.

butynediol and 9.4 percent formaldehyde, with the following results,referring to the letters of Example 1.

Calculated for w/x/y/z=12/3/2/5 (percent): A, 59.4; B, 2.6; C, 1.6; D,3.9. Found (percent); A, 59.5; B, 2.6; C, 2.0; D, 3.7; I, 92.

Examples 4-9 The general procedure of Example 1 was repeated severaltimes at the below-indicated acetylene partial pres- Initial 5 1 .1 I9050 1 m s w mw mm. 8754 mPmZN n n u O swm 877 322 m d m d U m 089 734 t.l n d5 h A m w m D 14 mmr m mfi wfi w u m 6m m0 :04 wmw 332436 N w m maP m w s .mx mwh 8011763 l fi EH LZLLLLL m a te m C 7677 ndpeg wPwm terrri wsdf H H u W vm u au o 2222222 h 1 I m 6 e m.m.w 4 efi w m 2 M mfl.wa B 6552 3 ln magma. w mw h nl 2 2 22 mwc i 5151515 2 m d m e 2 mL S neloh mma 0000000 2 e e h T 21 si t? 1...... aim... mm. m mO u wmw m 6 I2w%m m a m m mm a n Pl 15 n x mam e vn x mP m ME E d r O I: E d 709555558 Di en mi u C f 6777776 m0 M3 F..M m g F 6%% e T... ta S r N pfae 0 t i. g mm wm m m .mm n O sb W.I.P ctn y 3 w T O. m "fin" Irm D47170 0.554443 mm m mmwmh u "I" mmg 5 4326 ym e e .l n l e 60 t. d 6 13.1 m -1 S e g SS n t .l S. n m efim awm m II euWm 010613 nm h oas m mII m aarrr 111 mm lmn m m "I m i mnmwmmm D amswcp s 04mm vcm B 25617 O.10 0 0 0 F0 0 2 O4 3 3 4 A1 5 Z 12322 e e ddd w vuuuu r 2h s e n n m A48165 H /UU// a t te m w 5 L7 5 & fl//Hfl Uffm e sf 50556 W66666 .6IDOOW wm 0 S d brlemp T. 98357 m mm m m LLLO v .1 s r a h 0 tUCW T/0000. afa rX 3 T. 90 050 Z mcho .WZZ/ 9 2 4 8 n W E 58895 e f l H m 0 PC t h y r l Wm 0 m n f 5 53843 D 32389 H m a w m mv n l w m mO 4 3 3 wmm: I k wewm m 2 a l C. l 0 mm w ma w 2 s mmmm w m 29.; 11 I e 1O 1..aaa 31 h 66543 e D. B H um 0 cm W d 001955 0 X1E 1 22222 t H 1 Ed Ht 4 ea C O U @2371 .m O a 10072 A 55619 mumfwm m m wm nam aaeaa mmmmm w wma mo mLm S 8.1 8990 w face -1 a... a $5 a a m wm w mm E g mma 1103 e r 9 6nc p 7 a a rul 0 l r r. A 6 mfmm m P h mmm o rf a a mn 9 6 I a l .l 10 mmm wwww u 17H m m mfifl n e v. 6H 6 adaO mh m .CCfe nmP f. o a n ei W sprd xWh w m mm .LQIC. QHB m n 9 m maw bm x. z.m .vw mm E 4 imw s aumrr m(15) In contrast under these same general conditions square meters pergram, and containing less tha n 0.2 percent sulfur calculated assulfate. Spec1al conditlons and =2.1, results are set forth below,referring to the letters of Ex- =2.0, D=4.8, F=4, I=11. Calculated forample l and the following letters.

(a) Example No. (CuC (H O) (b) Precursor (c) Precursor wt., g. =2.0,0:2.0, D=4.8. Calculated W/X/y/Z 1) Calcium carbonate added, g valuesfor the complexes of Examples 10 to 15, respective- Catalyst preparationtime, including, after the l,

17/4/2/5; 16/4/3/9; 10/ 3/2/7; indicated hours under activity testingconditions 16/5/3/3; and 100/2/3/43. (f) Notes but at an acetylenepartial pressure of 1.2 atmosphere and 40 C. during a catalystpreparation, A=66.0, B

1y, were 17/1/1/6;

a b c d e f A B C D F I 27 C110 21.1 26/11 63.9 2. 2 1. 7 4. 7 16 C11021. 1 10 24/6. 5 (i) 62. 3 2. 0. 7 2. 2 31 29 Cu (P04)r3Ha0 40. 9 16 (2)61.0 2. 9 1. 3.8 72 30..- CuSiOr 39.0 0 3/7.5 (a) 52.5 2.6 1.5 0.3 52 31Cu(OH): 26.0 3 60. 9 2. 4 1. 5 3. 9 72 32 Cu(OH)z 26. 0 0 9/6 63. 2 2.4 1. 8 5. 3 35 33 CllCOa-CIKOH): 20. 8 0 3 (4) 61. 8 2. 5 2.0 4. 8 43 34CuCOg-CMOH); 30.4 3 (5) 58.6 2.6 1.6 3.7 88

1 Catalyst analyses corrected for calcium carbonate on basis of calciumanalysis. 2 Catalyst analyses corrected for calcium phosphate andunroacted copper phosphate on basis of calcium and phosphorous analyses.

3 Catalyst analyses corrected for silica. on the basis of siliconanalysis. 4 Precursor CuO/CO; mole ratio 2.89. 5 Precursor CuO/COz moleratio 1.95. Uncorrected cuprous copper analyses exceeded percent.

Examples 35-38 Percent Component: of total In contrast to the precedingset of examples, the gen- Methan l 0,9 eral procedure of Example 1 wasrepeated uslng 26.1 Water 68.9 grams of cuprous chloride precursorhaving a particle 20 Formaldehyde 2.2 size range of up to 35 microns,13.2 grams of calcium Propargyl alcohol 0.4 carbonate buffer, and areaction temperature of 90 C. Z-butyne-l-ol 4.5

under a acetylene partial pressure of 0.5 atmosphere. The product wassubjected to three successive cycles of activity testing, with a sampleof the catalyst being removed for analysis after each cycle. Resultswere as 'follows, referring to the letters of Example 1. Analyses werecorrected for calcium carbonate on the basis of calcium analysis.

Ex. No. Cycle A B C D I 35 Make 73.3 1.2 1.7 2.6 72 36 First 74.8 1.52.4 8.3 72 37.. Second 75.3 1.2 1.3 3.6 38 Third 73.9 1.4 1.3 4.8 76

After the third cycle, the catalyst comprised, by Coulter Counteranalysis, over 50 percent of particles smaller than 5 microns. Theparticles were contaminated with metallic copper, were relatively softand sticky, and were unsuitable for use in a continuous stirred reactionbecause of poor filterability. The elemental analyses of complexes ofExamples 35-38 correspond closely to with a, b, 0 values, respectively,of 9/2/8; 6/3/2; 6/1/4; and 5/2/ 3.

Example 39 Example 40 The general procedure of Example 1 was repeatedexcept that in the activity testing, the acetylene was replaced by amixture of acetylene and methyl acetylene containing 0.8 to 2.0 moles ofacetylene per mole of methyl acetylene. The I value was 53. The liquidremaining after 92 percent of the formaldehyde charged had reacted hadthe following constitution.

1,4-butynediol 24.1

Examples 41-44 The general procedure of Example 1 was repeated severaltimes using basic cupric carbonate precursors containing less than 0.02percent sulfate ion, having Coo/CO mole ratios in the range of 1.86 to2.13 and having the below-indicated values of (i) average particle sizeas determined by Coulter Counter analysis, (k) percent particles largerthan 5 microns, and (1) total surface area, m. /g., as determined bynitrogen absorption, with the following results referring to the lettersof Example 1, and (K) percent of catalyst particles larger than 5microns.

(k) (1) A B C D F I .T K

Examples 45-50 A catalyst preparation was carried out in a gas agitatedcylindrical stainless steel reactor having a working capacity of ca. 344parts of water. The reactor was purged with nitrogen to an oxygen levelof less than 0.5 percent by volume, and charged with 100 parts ofaqueous 53 percent formaldehyde and parts of water. The resultingsolution was adjusted to pH 6.8 with calcium carbonate, and then heatedto and maintained at ca. C. for the duration of the catalystpreparation. The water was then purged with a commercial acetylene,containing 0.041 part of methyl acetylene per part of acetylene,introduced near the bottom of the reactor and below the liquid surface,at a rate of ca. 0.75 liter (calculated at S.T.P.) per minute per partof liquid medium, under a total pressure of 1.5 atmosphere absolute,which was thereafter maintained throughout the catalyst preparation andsubsequent ethynylation. There was then added a slurry of 5 parts of thebasic cupric carbonate of Example 1 in 26 parts of water, followed bylike charges at intervals of 3 and 7 hours after the first coppercarbonate addition. The gas stream exiting from the reactor wasrecovered and recycled after establishing a purge to maintain anacetylenic compound content of percent on a dry basis. The catalyst makereaction was continued for an additional four hours. A sample of theresulting catalyst was removed for analysis and activity testing.

The reactor temperature was then raised to and maintained at C. The rateof acetylenic feed to the reactor was doubled and the same totalpressure over the liquid reaction medium maintained. When theformladehyde concentration in the liquid medium fell to 10 percent,

continuous removal of liquid efiiuent was commenced, the efiluent beingwithdrawn through cylindrical filter elements dipping below the liquidlevel in the reactor. The effluent was sent to a still and separatedinto a bottoms product stream consisting essentially of butynediol andwater, and an overhead stream consisting essentially of unreactedformaldehyde, methanol, propargyl alcohol and water. The overhead streamwas recycled to the ethynylation reaction, together with make-up 52aqueous percent formaldehyde sufiicient to maintain the formaldehydeconcentration in the liquid reaction medium at ca. percent, and theformaldehyde conversion across the reactor at ca. 80 percent. Thereaction medium was maintained substantially neutral by periodicaddition of calcium carbonate. The continuous stirred reaction wascontinued in this manner for 38 operating days, during which timebutynediol was obtained at an average rate of ca. 4 kilograms per literof catalyst slurry per day. Samples of the catalyst were removed atintervals for analysis. Results were as follows, referring to theletters of Example 1, the values of A through D being corrected forcalcium carbonate on the basis of calcium analysis, all catalysts havingF values greater than 15.0, being substantially free of metallic copper,and containing at least 85 weight percent of particles larger than 5microns.

In Example 50, when w=4, the w/x/y/z values are 4.00/4.00/2.40/1.60.

During this period of running the catalyst activity as judged by dailyproduction of butynediol decreased slightly to a substantially constantvalue after 4 days. Analysis of the effluent showed no trace of cupreneintermediates. The eflluent butynediol stream was continuously removedand subjected to catalytic hydrogenation on a continuous basis withsubstantially complete conversion to butanediol. There was no coating ofthe hydrogenation catalyst with organic material or consequent loss inhydrogenation activity. Explosibility tests on the dried ethynylationcatalysts showed them to be capable of detonation by heating at 162 C.for a minute or more, but substantially less sensitive than reportedcopper acetylides.

When a small sample was placed in a copper cup beneath a piston,dropping a 5 kg. weight from a height of 40 inches was required to causedecomposition of 50 percent of the samples tested, decomposition beingevidenced by small discolorations of the striker face with what appearedto be metallic copper. No smoke was evolved and no discolorationoccurred during impact testing, the bulk of the sample remaining in thecup being unaffected.

Example 51 The procedure of Example 45 was repeated, establishing abutynediol productivity of 3.8 kilograms per liter of catalyst slurryper day, at which point the continuous stirred reaction was interruptedby stopping the formaldehyde feed and liquid efliuent removal, theacetylene feed and venting being continued. The temperature of thereactor contents was then decreased in controlled steps, while theformaldehyde content decreased to 2.0 percent, after which formaldehydefeed was restarted, the temperature raised, and continuous removal ofliquid effluent again commenced as the formaldehyde content of thereaction mixture rose. Details are summarized below.

H C H O percent Hours after ECHO stopped Remarks Start cooling.

Hold temperature.

Start cooling.

Hold temperature.

Resume HCHO feed and efliuent removal.

Start heating.

Continuing under the last-named conditions, the butynediol productivitywas initially 2.0 kilograms per liter of catalyst slurry per day, anddid not improve on further running. Similar decreases in re-establishedproductivity were also observed when established continuous stirredreactions were similarly interrupted by shutting off acetylene feed fora time while maintaining HCHO feed. However, when temporary shutdown wasaccomplished by simultaneously and gradually changing to feeding Waterand nitrogen instead of formaldehyde and acetylene and cooling, and thereaction restarted by heating and then simultaneously resumingformaldehyde and acetylene feeds, no loss in productivity occurred.

Although the invention has been described and exemplified by way ofspecific embodiments, it is not intended that it be limited thereto. Aswill be apparent to those skilled in the art, numerous modifications andvariations of these embodiments can be made without departing from thespirit of the invention or the scope of the following claims.

I claim:

1. A particulate cuprous acetylide complex which consists essentially ofcopper, carbon, hydrogen and oxygen in proportions corresponding to thegeneral formula wherein the subscript letters are integers and each ofw, x and y is at least 1 and less than 100, contains at least 1.75carbon atoms per copper atom, as determined by combustion analysis afterfiltering, water washing, air drying and final drying over anhydrouscalcium sulfate for 3 days, and has a total surface area of at least 5square meters per gram, at least 75 weight percent of the complexparticles having a cross-sectional dimension of at least 5 microns, saidcomplex being prepared by the simultaneous action of formaldehyde andacetylene on a particulate water-insoluble cupric compound.

2. The complex of claim 1 which has a total surface area of at least 15square meters per gram.

3. The complex of claim 2 which contains at least 2 carbon atoms percopper atom.

4. The complex of claim 2 which contains at least 20 weight percentcuprous copper.

5. The complex of claim 4 which contains, per carbon atom, at least 0.2hydrogen atom and at least 0.1 oxygen atom.

6. The complex of claim 5 which is substantially free of metalliccopper.

7. The complex of claim 6 which has a total surface area of 15 to 75square meters per gram, comprises at least 75 weight percent particleshaving a cross-sectional dimension of 5 to 40 mircons, and contains 20to 66 weight percent copper, 2 to 12.5 carbon atoms per copper atom, 0.2to 2 hydrogen atoms per carbon atom, and 0.1 to 1 oxygen atom per carbonatom.

8. The complex of claim 7 which has an average particle size of 10 to 20microns, and contains 40 to 62 weight percent copper, 2.5 to 5 carbonatoms per copper atom, 0.5 to 1 hydrogen atom per carbon atom, and 0.15to 0.5 oxygen atom per carbon atom.

9. The complex of claim 2 in which, when w=4, x:0.24 to 4.0, y=0.24 to2.40 and z=0.67 to 2.80.

10. The complex of claim 2 in which said cupric compound is selectedfrom the group consisting of cupric 15 oxide, cupric silicate, cupricphosphate, cupric hydroxide and basic cupric carbonates.

11. The complex of claim in which said cupric compound is a basic cupriccarbonate.

12 A process for preparing a particulate cuprous complex which comprisessubjecting a particulate water-insoluble cupric compound, as a slurry inaqueous medium, at 50-120 C., to the simultaneous action of formaldehydeand acetylene at a partial pressure of not more than 2 atmospheres, saidaqueous medium having a pH of 3 to 10 at the initiation of saidsubjecting, and continuing the reaction until a complex corresponding toclaim 1 is obtained.

13. The process of claim 12 in which said aqueous medium has a pH of 5to 8 at the initiation of said subjecting.

14. The process of claim 13 in which said cupric compound is selectedfrom the group consisting of cupric oxide, cupric silicate, cupricphosphate, cupric hydroxide and basic cupric carbonates.

15. The process of claim 13 in which said cupric compound is a basiccupric carbonate.

16. The process of claim 15 in which said basic cupric carbonate is asynthetic malachite having a total surface area of at least 5 squaremeters per gram, consisting essentially of particles having across-sectional dimension of at least 2 microns, having a mole ratio ofCuO to CO in the range of 1.8 to 2.2, and containing less than 0.2weight percent sulfur, calculated as sulfate ion.

17. The process of claim 14 in which the concentration of formaldehydein said aqueous medium is at least 5 weight percent and the partialpressure of acetylene over said medium is in the range of 0.005 to 0.5atmosphere per weight part of formaldehyde present in 100 Weight partsof said aqueous medium.

18. The process of claim 17 in which the pH of said aqueous medium atthe initiation of said subjecting is in the range of 6 to 7, and saidtemperature is in the range of to C.

19. The process of claim 18 in which said particulate cupric compound isa basic cupric carbonate.

20. The process of claim 18 in which said partial pressure of acetyleneis in the range of 0.01 to 0.3 atmosphere per weight part offormaldehyde present in weight parts of said aqueous medium.

21. The process of claim 20 in which said temperature, formaldehydeconcentration and acetylene pressure are maintained until substantiallyall of said cupric precursor is converted to cuprous acetylide complex.

22. The process of claim 21 in which the pH of the aqueous medium duringthe course of said subjecting is maintained in the range of 3 to 10.

23. The process of claim 22 in which said particulate cupric compound isa synthetic malachite having a total surface area of at least 5 squaremeters per gram, consisting essentially of particles having across-sectional dimension of at least 2 microns, having a mole ratio ofCuO to CO in the range of 1.8 to 2.2, and containing less than 0.2weight percent sulfur, calculated as sulfate ion.

References Cited UNITED STATES PATENTS PATRICK P. GARVIN, PrimaryExaminer US. Cl. X.R. 260438.1

